ABSTRACT
Background: Electrospinning is an effective method for producing high-quality biopolymer nanofibers, such as cellulose and chitosan. Cellulose nanofibers have excellent mechanical properties and biocompatibility, making them a promising material for tissue engineering. Chitosan nanofibers are biodegradable, biocompatible, and antimicrobial, making them ideal for biomedical applications. The electrospinning parameters, including solution concentration, power supply voltage, orifice diameter, temperature, humidity, and flow rate, play a crucial role in determining the nanofiber diameter, morphology, and mechanical properties, as well as their suitability for various applications. Objective: This systematic review aims to synthesize and evaluate the current evidence on the influence of electrospinning parameters on the production and properties of cellulose and chitosan nanofibers. Methods: A comprehensive search of electronic databases was conducted to identify relevant studies. The inclusion criteria were studies that investigated the effect of electrospinning parameters on cellulose and chitosan nanofibers. Results: It was found that for cellulose, the average fiber diameter increased with increasing each of solution concentration, power supply voltage, orifice diameter, temperature, and humidity. Contrary to tip - collector distance and some optimal points in temperature, where average fiber diameter decreased. For chitosan, the change in voltage and tip to collector distance did not alter the average fiber diameter except for some readings of voltage, which behaved differently. On the other hand, the average fiber diameter increased with increasing flow rate. Conclusion: The review highlights the importance of considering electrospinning parameters in the production of high-quality biopolymer nanofibers and provides insights into the optimization of these parameters for specific applications. This review also highlights the need for further research to better understand the underlying mechanisms of electrospinning and to optimize the process to produce biopolymer nanofibers with improved properties.
ABSTRACT
Friction stir spot welding (FSSW) is one of the most popular fusion joining processes. The process is a solid-state welding process that allows welding of weldable as well as non-weldable materials. As a part of this investigation, weld samples of Al6061-T6 were reinforced with silicon carbide (SiC) powder with an average particle size of 45 µm. Initially, a Taguchi L9 orthogonal array was developed with three factors, i.e., rotational speed of the tool, pre-dwelling time, and diameter of the hole that was filled with SiC before welding. The effects of the SiC particles and process parameters were investigated as tensile-shear load and micro-hardness. The optimisation of parameters in order to maximise the output responses-i.e., strength and hardness of the welded joints-was performed using a hybrid WASPAS-Taguchi method. The optimised process parameters obtained were a 3.5 mm guiding hole diameter, 1700 rpm tool rotation speed, and 14 s of pre-dwelling time.
ABSTRACT
Composite materials are emerging as a vital entity for the sustainable development of both humans and the environment. Polylactic acid (PLA) has been recognized as a potential polymer candidate with attractive characteristics for applications in both the engineering and medical sectors. Hence, the present article throws lights on the essential physical and mechanical properties of PLA that can be beneficial for the development of composites, biocomposites, films, porous gels, and so on. The article discusses various processes that can be utilized in the fabrication of PLA-based composites. In a later section, we have a detailed discourse on the various composites and nanocomposites-based PLA along with the properties' comparisons, discussing our investigation on the effects of various fibers, fillers, and nanofillers on the mechanical, thermal, and wear properties of PLA. Lastly, the various applications in which PLA is used extensively are discussed in detail.
ABSTRACT
AIMS: To assess the prevalence of microvascular and macrovascular complications of type 2 diabetes (T2DM) among Palestinians. METHODS: 1308 diagnosed T2DM attending four main Primary Health Care Clinics on the Southern West Bank of Palestine examined by a Mobile Diabetes Clinic team. All diabetes patients visiting the clinics during a one-month period for each clinic were included. Interviews, anthropometric measurements, physical examination, and laboratory tests: HbA1c, lipid profile, and kidney function tests analyzed in a central laboratory were obtained RESULTS: 1308 diabetes patients, including 839 females (64%), with a mean age of 57 years (SD=8.7), and mean diabetes duration 7.1 years(SD=6.25), participated. 95.3% presented as overweight (BMI >25kg/m2) or obese (BMI>30kg/m2) with mean BMI of 33.46 (SD=5.95). The mean HbA1c (tested in 1221 patients) was 9.21(SD=2). Only 16.1% had HbA1c <7.0%. Hypertension (blood pressure>140/90mmHg) were found in 23%, and dyslipidemia (total cholesterol>200mg/dl) was present in 37.3% of patients. 213(16.3%) had a history of the macrovascular disease (previous myocardial infarction or stroke), and 290 (25.9%) had microvascular complications. Moreover, 40 (4.9%) had advanced kidney disease with serum creatinine>1.4mg/dl. CONCLUSIONS: The present cross-sectional study shows poor glycemic control in Palestine, while blood pressure and lipids are less poorly controlled. The study emphasizes the need to optimize the glucose-lowering treatment and to implement diabetes care program that could face the challenge of high uncontrolled diabetes as well as complications of diabetes.
